Zhang Juan, Zhang Shuai, Qi Wen-Jun, Xu Cong-Lin, Zhou Jie, Wang Jiang-Hong, Wang Bao-Li
Department of Prosthodontics, Tianjin Medical University and Hospital of Stomatology, Tianjin, China.
NHC Key Lab of Hormones and Development, Tianjin Key Lab of Metabolic Diseases, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China.
Oral Dis. 2023 Apr;29(3):1060-1069. doi: 10.1111/odi.14061. Epub 2021 Nov 10.
To investigate the mechanism of and potential contributing factors to temporomandibular joint osteoarthritis (TMJOA) caused by oestrogen deficiency with a persistent high bite force.
A TMJOA model was generated by subjecting 6-week-old female rats to ovariectomy (OVX) and feeding them a hard feed. The rats (n = 12/group) were divided into sham (control); OVX; OVX+hard feed (HF); OVX+hard feed+local-joint injection of 17β-oestradiol (an oestrogen) (E2); and OVX+hard feed+local-joint injection of rapamycin (an autophagy activator) (RAPA)groups. Condyles were stained with haematoxylin-eosin and Safranin O Fast Green. The expression of Beclin 1, LC3 and p-mTOR in condylar cartilages was analysed.
Tissue staining revealed thinner condylar cartilage, varying numbers or fewer hypertrophic chondrocytes, and lower proteoglycan content in the cartilage matrix of the OVX group. These characteristics were more pronounced in the HF group, but were significantly recovered in the E2 and RAPA groups. Immunohistochemical staining revealed significantly lower autophagic flux in OVX/HF groups and a higher one in E2/RAPA groups.
A persistent high bite force could aggravate TMJOA induced by oestrogen deficiency, and the application of oestrogen or rapamycin could delay its progression. Additionally, autophagy may play a role in the development of TMJOA.
探讨雌激素缺乏伴持续高咬合力导致颞下颌关节骨关节炎（TMJOA）的机制及潜在影响因素。
对6周龄雌性大鼠进行卵巢切除术（OVX）并给予硬饲料，建立TMJOA模型。将大鼠（每组n = 12只）分为假手术组（对照组）；OVX组；OVX+硬饲料（HF）组；OVX+硬饲料+局部关节注射17β-雌二醇（一种雌激素）（E2）组；以及OVX+硬饲料+局部关节注射雷帕霉素（一种自噬激活剂）（RAPA）组。髁突用苏木精-伊红和番红O固绿染色。分析髁突软骨中Beclin 1、LC3和p-mTOR的表达。
组织染色显示，OVX组髁突软骨变薄，肥大软骨细胞数量不同或减少，软骨基质中蛋白聚糖含量降低。这些特征在HF组中更为明显，但在E2组和RAPA组中明显恢复。免疫组织化学染色显示，OVX/HF组自噬通量显著降低，E2/RAPA组自噬通量较高。
持续的高咬合力可加重雌激素缺乏诱导的TMJOA，应用雌激素或雷帕霉素可延缓其进展。此外，自噬可能在TMJOA的发生发展中起作用。
